After Batman apprehends all villains, there are little converstaion scenes between Batman and Villains. Also, if you don't finish the final Scarecrow mission and do all other Most Wanted missions then you'll get to listen what Joker says about them. For some reason you cannot do Copplepot's Gunrunner mission without finishing the main story. I think it is because the final conversation between Batman and Nightwing. Also, you cannot talk to Scarecrow as he is in Bat fear by his own fear toxin. Enjoy!
Batman Arkham Knight - All Villains Conversations
Batman Arkham Knight Villains Conversations
Batman Arkham Knight Conversations
